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Finding the Fourth Proportional to 1,008, 1,389.83 and 821.09

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Solution

The fourth proportional to 1,008, 1,389.83 and 821.09 is: 1,132.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,008 : 1,389.83 = 821.09 : x
  2. Step 2: Convert to fraction form
    1,008/1,389.83 = 821.09/x
  3. Step 3: Cross multiply
    1,008x = 1,389.83 × 821.09
  4. Step 4: Simplify right side
    1,008x = 1,141,174.88
  5. Step 5: Solve for x
    x = 1,141,174.88/1,008
  6. Step 6: Final answer
    x = 1,132.12

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.